| 主权项 |
1. An exhaust fan assembly comprising:
a substantially cylindrical outer enclosed wall having an air inlet and an air outlet, the outer enclosed wall including at least one elongated opening; an inner enclosed wall being positioned within the outer enclosed wall and including at least one elongated opening; an annular space defined between the inner enclosed wall and the outer enclosed wall, wherein an upper ends of the inner enclosed wall and the outer enclosed wall form a nozzle; a windband mounted proximate the nozzle; a roof and a bottom plate secured to the inner enclosed wall, wherein the roof, the bottom plate, and the inner enclosed wall define a bearing chamber; a fan disposed within the outer enclosed wall, the fan being configured to move exhaust air through the air inlet, the annular space and the air outlet; a rotatably mounted shaft connected to the fan, the shaft extending into the bearing chamber; and a passage wall extending between the elongated openings of the inner and outer enclosed walls, wherein the elongate opening of the outer enclosed wall, the passage wall, the elongate opening of the inner enclosed wall, the roof, and the windband form an air passageway for a volume of ambient air to be drawn into the elongate opening of the outer enclosed wall, along the passage wall, into the elongate opening of the inner enclosed wall, above the roof, and out of the windband, without the volume of ambient air entering the bearing chamber, and wherein the passage wall also provides an access to the bearing chamber separate from the air passageway. |
